Change the access mode
of one or more files
. Only the owner of a file or a privileged user may change its mode. Create mode
by concatenating the characters from who
, opcode
, and permission
. who
is optional (if omitted, default is a
); choose only one opcode
.

Alternatively, specify permissions by a three-digit sequence. The first digit designates owner permission; the second, group permission; and the third, others permission. Permissions are calculated by adding the following octal values:

4

Read

2

Write

1

Execute

Note: a fourth digit may precede this sequence. This digit assigns the following modes: